Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “pathogen isolation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 793 records · Page 44Linked to original sources
PubMed2002

Bacterial colonisation in patients with bronchiectasis: microbiological pattern and risk factors.

BACKGROUND: A study was undertaken to investigate the incidence, diagnostic yield of non-invasive and bronchoscopic techniques, and risk factors of airway colonisation in patients with bronchiectasis in a stable clinical situation. METHODS: A 2 year prospective study of 77 patients with bronchiectasis in a stable clinical condition was performed in an 800 bed tertiary university hospital. The interventions used were pharyngeal swabs, sputum cultures and quantitative protected specimen brush (PSB) bacterial cultures (cut off point > or =10(2) cfu/ml) and bronchoalveolar lavage (BAL) (cut off point > or =10(3) cfu/ml). RESULTS: The incidence of bronchial colonisation with potential pathogenic microorganisms (PPMs) was 64%. The most frequent PPMs isolated were Haemophilus influenzae (55%) and Pseudomonas spp (26%). Resistance to antibiotics was found in 30% of the isolated pathogens. When the sample was appropriate, the operative characteristics of the sputum cultures were similar to those obtained with the PSB taken as a gold standard. Risk factors associated with bronchial colonisation by PPMs in the multivariate analysis were: (1) diagnosis of bronchiectasis before the age of 14 years (odds ratio (OR)=3.92, 95% CI 1.29 to 11.95), (2) forced expiratory volume in 1 second (FEV1) <80% predicted (OR=3.91, 95% CI 1.30 to 11.78), and (3) presence of varicose or cystic bronchiectasis (OR=4.80, 95% CI 1.11 to 21.46). CONCLUSIONS: Clinically stable patients with bronchiectasis have a high prevalence of bronchial colonisation by PPMs. Sputum culture is a good alternative to bronchoscopic procedures for evaluation of this colonisation. Early diagnosis of bronchiectasis, presence of varicose-cystic bronchiectasis, and FEV1 <80% predicted appear to be risk factors for bronchial colonisation with PPMs.

Adolescent↗
PubMed1984

Bacterial sinusitis.

Sinusitis may occur secondary to infectious agents, allergens, or pollutants. Bacteriologic studies carried out from sinus punctures revealed that Streptococcus pneumoniae and Hemophilus influenzae are the most common bacterial pathogens isolated. Staphylococcus aureus and Streptococcus pyogenes are not uncommon pathogens. Complications of sinusitis, including orbital cellulitis, usually are due to infection with Staphylococcus aureus and H influenzae. The recent increase in certain areas of the country of beta-lactamase-producing strains of H influenzae is noted. When the etiology remains to be determined in the patient with acute bacterial sinusitis, initial therapy with an oral cephalosporin seems warranted.

Acute Disease↗
PubMed1995

[Survey of disease of cultural shrimp in Taiwan].

The large number of hemocytes infiltrated several abnormal tissues of kuruma shrimp (Penaeus japonicus), including musculature, hepatopancreas, lymphoid organ, gill filament and sponge tissue. In addition, there were many denatured hemocytes existing inside acidophilic particles and forming granules. Futhermore, in hepatopancreas of kuruma shrimp, a white spot baculovirus (WSBV; 40-50 x 50-300 nm) was discovered in UH (undifferential haemocyte). The epithelium cells, which including stomach cuticle and underlying epidermis of exoskeletal cuticle, could also be infected by WSBV in another main cultural species--grass shrimp (P. monodon). During a period of high water temperature, with pond shrimp in normal condition, the CFU/ml of water bacteria rose from 10(5) to 10(7), but this number had decreased to 10(5) CFU/ml by the time moribund shrimp began to appear. Coincidentally, the total bacterial number isolated from hepatopancreas and musculature of moribound shrimp was over 10(5) (CFU/g) and 10(3)-10(5), respectively. The fauna of bacteria was taken over by the active metabolitic species which were represented by Vibrio species causing the pond shrimp to undergo either behavioral changes, such as swimming on the water surface, or histological changes, such as having whitish muscle color, hemocyte infiltration and granuloma formation etc. Pathogenetic species of Vibrio including V. parahaemolyticus, V. alginoly ticus V. anguillarum, V. fischery and V. damsela were isolated from those tissues of moribund shrimp. The main pathogens, isolated from musculature and hepatopancreas, were V. parahaemolyticus and V. alginolyticus. On the other hand there, was no bacterium could be isolated from the musculature of healthy shrimp and only a single species of Gram (+) coccus--Micrococcus--was isolated from the tissue of hepatopancreas.

Animals↗
PubMed1995

Antimicrobial activity of 11 newer and investigational drugs tested against aerobic isolates from spontaneous bacterial peritonitis.

The in vitro susceptibility of 124 aerobic bacterial pathogens isolated from patients with spontaneous bacterial peritonitis (SBP) were tested against 11 antimicrobial agents, including parenteral or oral cephalosporins and fluoroquinolones. Most SBP isolates were Gram-negative organisms, and Escherichia coli and Klebsiella pneumoniae were responsible for 63% of the episodes evaluated. The fluoroquinolones (ciprofloxacin and ofloxacin) and the "fourth-generation" cephalosporin cefpirome were the most active agents against the Gram-negative bacteria. Commonly used cefotaxime and cefotaxime-desacetylcefotaxime (DES-CTX) combinations were also very active against Gram-negative bacteria with only few Enterobacter cloacae isolates being resistant (minimum inhibitory concentrations > 32 micrograms/ml). All streptococci were susceptible to cefotaxime, cefpirome, and cefdaloxime and to the cefotaxime-DES-CTX combinations, whereas only ofloxacin demonstrated acceptable activity against the enterococci. The widest spectrum of activity versus SBP isolates was found for ofloxacin (98% susceptibility) among the fluoroquinolones. For the beta-lactams, the widest spectrum of activity was demonstrated by cefpirome and the 2:1 cefotaxime-DES-CTX combination (93% susceptibility). These results indicate that the role of ofloxacin and newer parenteral or orally administered cephalosporins in the treatment of prophylaxis of SBP should be further evaluated.

Anti-Bacterial Agents↗
PubMed1996

The cloned gene, Xa21, confers resistance to multiple Xanthomonas oryzae pv. oryzae isolates in transgenic plants.

The cloned rice gene, Xa21, confers resistance to multiple pathogen isolates of Xanthomonas oryzae pv. oryzae in transgenic plants. The resistance phenotype was stably transmitted to T1 progeny and inherited as a single locus. The T1 progeny were tested for resistance to 32 X. oryzae pv. oryzae isolates from eight countries. Both the engineered line and the donor line showed resistance to 29 isolates and susceptibility to three isolates. The identical resistance spectrum of both lines indicates that the presence of a single member of a multigene family, Xa21, is sufficient to confer multi-isolate resistance. The results presented here have important implications for engineering disease resistance in crop plants.

Base Sequence↗
PubMed1988

Sensitivity of clinical isolates from German hospitals to amoxicillin/clavulanic acid (Augmentin) compared with other antibiotics.

17,244 pathogens isolated from clinical specimens of 24 hospitals in the Moers area (North-Rhine Westphalia, FRG) were tested in regard to their susceptibility to Augmentin (amoxicillin and clavulanic acid). For this purpose, minimal inhibitory concentrations were determined by use of microbroth dilution technique. 80% of Gram-negative, 98% of Gram-positive and 97% of anaerobic isolates were susceptible to Augmentin (breakpoint 4 mg/l amoxicillin in the presence of 2.5 mg/l clavulanic acid). In a second part of the study the susceptibility to Augmentin of 4.137 Gram-negative and 10.958 Gram-positive pathogens was compared to their sensitivity against benzylpenicillin, flucloxacillin, mezlocillin, erythromycin, clindamycin, fusidic acid, ampicillin, cefaclor and doxycyclin.

Amoxicillin↗
PubMed1991

Preliminary field evidence for the association of clinical mastitis with altered interestrus intervals in dairy cattle.

Clinical mastitis and reproductive records from two southern California dairy herds were used in a cross-sectional study to determine the risk of an altered interestrus interval following clinical mastitis. An altered interestrus interval was defined as cycles occurring at either less than 18 day or more than 24-day intervals. The data were stratified by herd to assess herd differences and by lactation number to assess confounding by cow parity. The predominant pathogen isolated from mastitis cases in Herd 1 was Staphylococcus aureus , whereas the predominant pathogens in Herd 2 were gram-negative isolates. Cows in Herd 1 which had coliforms cultured from mastitic milk were excluded in the analysis for comparison with Herd 2. In Herd 1, cows with clinical mastitis were less likely to have an altered interestrus interval (Relative Risk [RR]=0.9; 95% Confidence Interval [CI]=0.6,1.6) than herdmates without clinical mastitis. However, cows in Herd 2 were almost two times more likely to have an altered interestrus interval following an episode of clinical mastitis compared to herdmates without clinical mastitis (RR=1.6; 95% CI=1.3,2.0). Because herd management practices differ and could cause differences in mastitis and reproductive outcomes at the dairies, this preliminary field evidence should be followed by prospective studies of luteal function after clinical coliform mastitis.

Journal Article↗
PubMed1991

Differentiation of pathogenic from nonpathogenic Entamoeba histolytica by restriction fragment analysis of a single gene amplified in vitro.

We previously reported the identification of homologous cDNA clones derived from a pathogenic isolate and a nonpathogenic isolate of Entamoeba histolytica, which had been designated cEh-P1 and cEh-NP1, respectively. Sequence analysis of both clones had revealed 10% nucleic acid substitutions, which were dispersed over the entire sequence. This genetic difference had been found to be conserved between all four pathogenic and all five nonpathogenic laboratory strains of E. histolytica tested. On the basis of nucleic acid substitutions, we have now developed a sensitive assay to distinguish pathogenic from nonpathogenic forms of E. histolytica by using fresh clinical isolates. Comparing the sequence of cEh-P1 and cEh-NP1, we identified a 482-bp segment that contained identical 5' and 3' ends but differed in internal cleavage sites for restriction endonucleases. By using oligonucleotide primers corresponding to the 5' and 3' ends of this segment, the corresponding gene was amplified by the polymerase chain reaction. Endonuclease digestion of the amplified DNA yielded restriction fragments that are characteristic for pathogenic and nonpathogenic forms. This assay allows the detection and classification of fewer than 10 amoebae within a few hours. The differentiation of 48 isolates into pathogenic and nonpathogenic strains by using this method corresponded to the clinical status of the infected individuals and to the classification obtained by isoenzyme determination. The results further support the concept that pathogenic and nonpathogenic strains of E. histolytica constitute distinct subspecies.

Animals↗
PubMed2006

Significant difference in pathogenicity between MAT1-1 and MAT1-2 isolates in the wheat pathogen Mycosphaerella graminicola.

Five Mycosphaerella graminicola populations from four geographic regions (Australia, Israel, Switzerland, and the USA) were assayed for neutral RFLP markers and mating type idiomorphs. On average, 25-30 genetically distinct isolates were selected from each population and their pathogenicity was measured on two wheat cultivars in a common garden experiment conducted in a greenhouse. A significant difference in pathogenicity was found between MAT1-1 and MAT1-2 isolates. On average, MAT1-1 isolates had 14-22% greater pathogenicity than MAT1-2 isolates. The pattern of higher pathogenicity in MAT1-1 isolates was consistent across four geographical populations and on two wheat cultivars. A uniform and continuous variation in pathogenicity was found among isolates within each mating type, but no genetic differentiation in selectively neutral RFLP loci was found between mating types, consistent with the hypothesis that differences in pathogenicity were not due to the effects of specific pathogenicity genes or non-random genetic backgrounds.

Ascomycota↗
PubMed2005

In vitro activity of tigecycline against isolates from patients enrolled in phase 3 clinical trials of treatment for complicated skin and skin-structure infections and complicated intra-abdominal infections.

The in vitro activity of tigecycline was evaluated against 4913 baseline pathogens isolated from 1986 patients enrolled in 4 pivotal phase 3 clinical trials. The trials, which were conducted in 38 countries worldwide, involved patients with complicated skin and skin-structure infections or complicated intra-abdominal infections. Tigecycline was active against the most prevalent pathogens for each infection type, including gram-positive and gram-negative strains of both aerobic and anaerobic bacteria (MICs, < or =2 microg/mL for most pathogens). The spectrum of activity of tigecycline included important pathogens, such as Staphylococcus aureus (including methicillin-resistant S. aureus), Streptococcus pyogenes, Escherichia coli, Klebsiella pneumoniae, and Bacteroides fragilis. A few genera, such as Pseudomonas aeruginosa and members of the tribe Proteeae, were generally less susceptible to tigecycline than were other gram-negative pathogens. The susceptibility of the pathogens to tigecycline was similar for isolates obtained from patients enrolled in the studies of complicated skin and skin-structure infection or of complicated intra-abdominal infection. For most pathogens, the susceptibility to tigecycline was similar across all geographic regions. The excellent expanded broad-spectrum activity of tigecycline demonstrated in vitro against clinical isolates confirmed its potential utility for pathogens associated with complicated skin and skin-structure infections or complicated intra-abdominal infections.

Anti-Bacterial Agents↗
PubMed2003

[Distribution and resistance trends of pathogens from urinary tract infections and impact on management].

OBJECTIVE: To assess the bacterial profile and pattern of antibiotic resistance of urinary tract infections (UTIs) pathogens and to determine its clinical impact on management. METHODS: Midstream urine samples were submitted for culture from 1998 to 2002, and 798 isolates were obtained for antimicrobial susceptibility testing including amikacin (AMK), ampicillin (AMP), cefzolin (CFZ), cefuroxime (CXM), ceftriaxone (CRO), ceftaxime (CTX), ceftazidime (CAZ), nalidixoc acid (NAL), ciprofloxacin (CIP), trimethoprim/sulfamethoxazole (SXT), nitrofurantoin (NIT) for Gram-negative bacteria and oxcillin (OXA), ampicillin (AMP), cefzolin (CFZ), ciprofloxacin (CIP), gentamicin (Gen), vancomycin (VAN), trimethoprim/sulfamethoxazole (SXT), nitrofurantoin (NIT) for Gram-positive cocci. beta-lactamases and ESBLs were tested when needed. RESULTS: Enterobacteriaceae was the most frequently isolated pathogen. Among all the isolates, Escherichia coli accounted for 66.0%, followed by Enterococcus (6.5%), Klebsiella spp. (6.0%), Staphylococcus (5.4%). High resistance rates to CIP (56.0%), SXT (67.0%) and AMP (78.9%) were observed among the E. coli. CIP-resistant E. coli strains are being isolated with increasing frequency. From 1998 to 2002 the incidence of CIP-resistant increased steadily from 46.6% to 59.4%. A higher resistance rate to NAL was apparent. In contrast, NIT displayed a resistance rate of 8.9%, and AMK 4.9%. The ESBLs positive rate was 12.9% among the E. coli and 33.3% among the Klebsiella spp. respectively. A high resistance rate to CIP was also observed among the Staphylococcus (38.1%), Enterococcus (61.5%) and Streptococcus (85.0%), and the beta-lactamases positive rate was 95.2% among the Staphylococcus, but a lower resistance rate to NIT among Staphylococcus (2.4%) and Enterococcus (11.5%). CONCLUSIONS: Resistance rates among common uropathogens continue to evolve and appear to be increasing to many commonly used agents especially to quinolones. Continued surveillance of resistance rates among uropathogens is needed to ensure appropriate recommendations for the treatment of the infections. Currently, the most appropriate agent for the empirical management of UTIs seems to be nitrofurantoin.

Ciprofloxacin↗
PubMed1985

[Comparative studies of antimicrobial agents against causative organisms isolated from urinary tract infections (1983). III. Secular changes in susceptibility].

The in vitro antimicrobial activities of antibiotics against causative pathogens isolated from patients with urinary tract infections (UTI) in the 8 institutions in Japan during the period from 1980 to 1983 were compared. A number of new beta-lactam antibiotics with broad spectrum of activity have become available for clinical use in recent years. Some of them, in particular so-called third generation cephems, are reported to be responsible for developing microbial-cross resistance to multiple beta-lactam antibiotics. We have been making survey in recent years to explore changes in susceptibility to various antimicrobial agents of clinical isolates. All bacterial isolates from clinical specimens were submitted to the Department of Clinical Pathology, Juntendo University School of Medicine, where they were tested for antimicrobial susceptibility with MIC 2000 apparatus. Of all pathogens from patients with simple UTI, the majority of the isolates was E. coli and Klebsiella spp. In cases of complicated UTI, on the other hand, Pseudomonas spp. were most frequent, followed in order by Proteus spp., Klebsiella spp., Serratia spp., Citrobacter spp. and E. coli. Conspicuous changes in antimicrobial activity of antibiotics against E. coli and Klebsiella spp. from simple UTI have not been found in our survey. Against strains of Citrobacter spp., even the third generation cephems proved to be not remarkably active and there was a significant decrease in susceptibility of isolates to the drugs test-showed MIC values of 50 micrograms/ml and the proportion increased to 50% (22/44) with isolates obtained in 1982. The antimicrobial activity of cefsulodin and gentamicin against P. aeruginosa was decreased in 1982 compared with that in 1980 and 1981. However, resistant strains were slightly more frequent with gentamicin. In 1983, the antimicrobial activity of third generation cephems against Serratia spp. was significantly reduced from that in 1982.

Anti-Bacterial Agents↗
PubMed2005

Tigecycline activity tested against 26,474 bloodstream infection isolates: a collection from 6 continents.

The activity of tigecycline (formerly GAR936), a novel glycylcycline, was tested against recent bloodstream infection (BSI) pathogen isolates from 6 continents. Frequency of clinical occurrence of these pathogens was determined and their antibiograms assessed using reference broth microdilution methods. A total of 26474 strains were tested for tigecycline susceptibility according to the Clinical and Laboratory Standards Institute (formerly the National Committee for Clinical Laboratory Standards) by the M7-A6 guidelines with interpretations from M100-S15 and the package insert. The rank order of pathogens was Staphylococcus aureus (33.1%), Escherichia coli (14.0%), coagulase-negative staphylococci (13.5%), Enterococcus spp. (12.3%), Klebsiella spp. (5.7%), Pseudomonas aeruginosa (4.2%), Enterobacter spp. (3.0%), beta-hemolytic streptococci (2.9%), Streptococcus pneumoniae (2.3%), and viridans group streptococci (1.4%). Tigecycline exhibited a broader spectrum of activity against BSI isolates when compared to ciprofloxacin, tetracycline, aminoglycosides, and many beta-lactams (imipenem). Tigecycline was highly active against most pathogens tested, including staphylococci (MIC(90), 0.5 microg/mL), enterococci (MIC90, 0.25 microg/mL), streptococci (MIC(90), < or =0.12 microg/mL), Escherichia coli (MIC90, 0.25 microg/mL), Klebsiella spp. (MIC90, 1 mmicrog/mL), and Enterobacter spp. (MIC(90), 2 mmicrog/mL), but showed limited inhibition of Pseudomonas aeruginosa (MIC90, 16 microg/mL) and indole-positive or indole-negative Proteae (MIC90, 4-8 microg/mL). In summary, tigecycline exhibited a wide spectrum of antimicrobial potency versus BSI isolates collected worldwide. Serious infections in nosocomial environments should benefit from tigecycline use among the investigational phase 3 agents focused toward resistant strains.

Anti-Bacterial Agents↗
PubMed1989

Routine endotracheal cultures for the prediction of sepsis in ventilated babies.

Serial cultures of endotracheal tube aspirates were carried out in 94 neonates who were intubated and had been ventilated for longer than one week. A similar change in bacterial colonisation with duration of ventilation was seen in infants who subsequently developed sepsis and those who did not. In both groups, 177 aspirates (more than 90%) obtained during the first week of ventilation were sterile. Thereafter, colonisation with mixed Gram positive flora emerged followed by growth of Gram negative bacilli. For the infants who developed sepsis, the correlation between pathogens isolated from blood during the episodes of sepsis and those from previous endotracheal tube isolates was poor; in only five of the 26 cases of sepsis (19%) was the same single strain of organism isolated from culture of the blood and of the endotracheal tube aspirate. Other markers of infection such as endotracheal tube aspirate white blood cell counts and changes in bacterial flora were not useful in predicting systemic infection. Routine surveillance cultures of endotracheal tube aspirates in ventilated infants are not helpful in predicting the pathogens that are isolated from the blood during episodes of sepsis.

Cross Infection↗
PubMed1984

Characterization of isolates and clones of Leishmania by analysis of kinetoplast DNA.

The genetic characterization of pathogenic isolates of Leishmania was attempted by analysis of the molecular properties of kinetoplast DNA (kDNA) minicircles. Unit minicircle size is not conserved during speciation of Leishmania since the minicircles of strains and clones of L t major are smaller (700 bp) than those found in certain strains of L mexicana ssp (820 bp), L donovani (850 bp) or L t tropica (900 bp). Schizodeme analysis of minicircles reveals a high degree of sequence divergence in kDNA of Leishmania with the degree of microheterogeneity varying between species. This sequence divergence allows the discrimination of species, strains, and clones of Leishmania into schizodemes . Southern blot hybridization experiments reveal that at high stringency overall minicircle sequence homology is conserved among clones and strains of one species (L t major) but not between different species. This property of minicircle DNA permits the use of kDNA probes as a species-specific diagnostic test for the identification of unknown Leishmania isolates. The properties of kDNA from an L t tropica strain LRC- L32 (a " recidiva " organism) are so diverged from those of L t major strains as to support the classification [22, 23] of L t tropica and L t major as separate species of Leishmania rather than subspecies of L tropica.

Animals↗
PubMed2002

In vitro activity of ertapenem against common clinical isolates in relation to human pharmacokinetics.

The in vitro activity of ertapenem against bacterial pathogens isolated from patients with moderate to severe complicated intra-abdominal, complicated skin/skin structure, acute pelvic, or complicated urinary tract infection or community acquired pneumonia was compared to ceftriaxone and piperacillin-tazobactam and related to known plasma concentrations of the three agents. Ertapenem was more potent against methicillin-susceptible Staphylococcus aureus (MSSA) than ceftriaxone and piperacillin-tazobactam and was more potent and more active than both of these agents against Enterobacteriaceae and anaerobes. Piperacillin-tazobactam was the most active agent against enterococci and Pseudomonas aeruginosa. All isolates of Enterobacteriaceae (n=1088), Streptococcus pyogenes (n=37), Streptococcus agalactiae (n=48), MSSA (n=187), Haemophilus influenzae (n=59), and Moraxella catarrhalis (n=9) were susceptible to ertapenem; < 1% of 1284 anaerobes and only 1 of 113 Streptococcus pneumoniae (a penicillin-resistant isolate) were resistant to ertapenem. The MIC value at which 90% of all Enterobacteriaceae, streptococci, MSSA, H. influenzae, M. catarrhalis, and anaerobes were inhibited (MIC90) was < or = 1 microg/ml and below the mean plasma concentration of total ertapenem following a 1 g intravenous infusion for at least 24 hours, i.e., the entire recommended dosing interval, and below the free drug concentration for at least 8 h.

Anti-Bacterial Agents↗
PubMed2006

Evaluation of the effects of animal age, concurrent bacterial infection, and pathogenicity of porcine reproductive and respiratory syndrome virus on virus concentration in pigs.

OBJECTIVE: To evaluate the influences of animal age, bacterial coinfection, and porcine reproductive and respiratory syndrome virus (PRRSV) isolate pathogenicity on virus concentration in pigs. ANIMALS: Twenty-one 2-month-old pigs and eighteen 6-month-old pigs. PROCEDURE: Pigs were grouped according to age and infected with mildly virulent or virulent isolates of PRRSV. The role of concurrent bacterial infection was assessed by infecting selected pigs with Mycoplasma hyopneumoniae 21 days prior to inoculation with PRRSV. On alternating days, blood and swab specimens of nasal secretions and oropharyngeal secretions were collected. On day 21 after inoculation with PRRSV, selected tissues were harvested. Concentrations of PRRSV were determined by use of quantitative real-time PCR and expressed in units of TCID(50) per milliliter (sera and swab specimens) or TCID(50) per gram (tissue specimens). RESULTS: Concentrations of virus were higher in blood and tonsils of pigs infected with virulent PRRSV. Pigs infected with virulent PRRSV and M hyopneumoniae had significantly higher concentrations of viral RNA in lymphoid and tonsillar tissue. Coinfection with M hyopneumoniae resulted in a higher viral load in oropharyngeal swab specimens and blood samples, independent of virulence of the PRRSV isolate. Two-month-old pigs had significantly higher viral loads in lymph nodes, lungs, and tracheal swab specimens than did 6-month-old pigs, independent of virulence of the PRRSV isolate. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple factors affect PRRSV concentration in pigs, including pathogenicity of the PRRSV isolate, age, and concurrent infection with M hyopneumoniae.

Aging↗