peritonitis is still the leading cause of technique failure in continuous ambulatory peritoneal dialysis ( capd ) patients .
the incidence of peritonitis depends on the factors such as age , race , educational background , environment , and type of dialysis system used .
several studies have shown a decreasing trend in the gram - positive peritonitis and an increasing trend in the incidence of gram - negative peritonitis .
the microbiological spectrum of pd - related peritonitis seen in patients from developing countries such as india may be different from that observed in patients from developed countries , and it may be attributed to the difference in social , environmental , educational , and financial background , and surrounding climate of the patients .
the main modality of chronic dialysis for the patients of end - stage renal disease is chronic peritoneal dialysis ( pd ) at our center which is the only tertiary care hospital in the state of himachal pradesh providing dialysis services .
we analyzed our data regarding the incidence and outcome of the peritonitis caused by different types of microorganisms .
it was a prospective study involving patients undergoing capd at our center who developed peritonitis over a period of a year - and - a - half ( january 1 , 2009 to june 30 , 2010 ) .
the study was approved by the institutional ethics committee and an informed consent was obtained from the patients before their inclusion in the study .
the patients exchange bags containing effluent dialysate were delivered to the microbiology laboratory for culturing on the same day that they were collected from the patients .
the bags not processed immediately , were refrigerated at 4c . from these exchange bags ,
100 ml of fluid was withdrawn with a sterile needle and syringe under aseptic conditions .
this fluid was centrifuged in sterile tubes at a rate of 3000 g for 15 min and supernatant was discarded , leaving 0.5 ml of deposit . in the centrifuged deposit ,
10 ml of sterile distilled water was added and the mixture was shaken vigorously for 30 s. after vigorous shaking , the deposit was centrifuged at 3,000 g for 15 min and supernatant was discarded .
the deposit was divided into three parts , the first part of the deposit was used for gram staining , ziehl - neelsen ( zn ) staining , and 10% koh mount to detect the presence of yeast cells or fungal hyphae .
the second part of the deposit was used for culturing the bacteria which was done on blood agar ( ba ) and macconkey agar at a temperature of 37c for 24 - 48 h. culturing for fungi was done on sabouraud - dextrose agar with and without antibiotics at temperatures of 25c and 37c for 4 weeks , and culturing for mycobacteria was done on lowenstein jensen medium at 37c for 8 - 12 weeks .
the third part of the deposit was inoculated into brain - heart infusion ( bhi ) broth and incubated at 37c .
bhi broth was observed daily for the development of turbidity . after the development of turbidity , the fluid was gram - stained and plated on appropriate media for isolation and identification of the microorganisms .
the drug sensitivity was done by kirby - bauer disc diffusion method on mueller hinton agar . for gram - positive organisms , ampicillin , amoxi - clavulanic acid , cefazolin , clindamycin , and vancomycin discs
the cefoxitin discs were used to detect methicillin - resistant staphylococcus aureus ( mrsa ) . for gram - negative organisms , ciprofloxacin , cefotaxime , ceftriaxone , ceftazidime , cefepime , gentamicin , piperacillin 
tazobactam , and imipenem discs were tested as per clinical and laboratory standard institute guidelines for antimicrobial susceptibility testing .
there were 36 episodes of peritonitis in 25 patients during the study period ( 15 male patients , 11 diabetics , and mean age 58.4  9.1 years ) .
the mean duration of pd in these patients was 29.6  21.6 ( range 6 - 92 ) patient - months .
a total of 36 effluent dialysate bags from 36 consecutive patients of capd peritonitis were submitted for microbiological evaluation .
initial smear showed gram - positive cocci in 2 , gram - negative bacilli in 1 , and 1 showed yeast cells [ table 1 ] .
out of a total of 36 dialysate cultures , 33 ( 91.6% ) dialysate were culture - positive and the culture was sterile in 3 ( 8.4% ) [ figure 1 ] .
a total 36 microorganisms were isolated in 33 capd dialysate cultures . among the 36 microorganisms , 19 ( 52.8% )
isolates were gram - positive , 10 ( 27.8% ) isolates were gram - negative , 5 ( 13.9% ) isolates were fungi and 2 ( 5.6% ) mycobacterial spp .
were isolated [ table 2 ] . among the 19 gram - positive microorganisms , staphylococcus spp . 15
( 78.9% ) were the most common group of pathogens involved in capd peritonitis [ table 3 ] .
staphylococcus aureus accounted for 8 ( 22.2% ) , coagulase - negative staphylococcus ( cons ) 7 ( 19.4% ) , and 3 ( 8.33% ) isolates were enterococcus fecalis and one isolate was listeria monocytogenes .
among the 10 ( 27.8% ) gram - negative organisms : the microorganisms of enterobacteriaceae were isolated in 5 : e. coli 3 , klebsiella pneumoniae and enterobacter spp .
1 each , and environmental gram - negative bacilli were cultured in other 5 : pseudomonas spp .
. 2 . among the 5 ( 13.9% ) fungal isolates : candida albicans 1 , non - candida albicans spp 2 , and 1 each of rhizopus spp . and aspergillus flavus were recovered .
the culture also showed the growth of 1 ( 2.8% ) isolate each of mycobacterium tuberculosis and mycobacterium kansasii .
result of smear staining of the centrifuged dialysate ( total=36 ) result of continuous ambulatory peritoneal dialysis dialysate culture type of organisms isolated ( total=36 ) spectrum of microorganisms isolated in culture ( total=36 ) when we analyzed the organisms according to their origin [ figure 2 ] , the organisms of skin origin were more frequent ( 50% ) than the organisms of environmental origin ( 25% ) , followed by those of fecal origin ( 22% ) .
we considered staphylococcus aureus , cons , and candida spp . to be of skin origin .
origin of microorganisms isolated in culture gram - positive organisms were sensitive to all antibiotics which were tested .
all gram - negative organisms were sensitive to ciprofloxacin , ceftriaxone , cefataxime , cefepime , gentamicin , but klebsiella pneumoniae was resistant to beta- lactam antibiotics ( extended spectrum beta - lactamase producers [ esbl ] ) and was sensitive to imipenem .
there was an episode of recurrent peritonitis caused by staphylococcus aureus in one of the capd patient and when nasal swab of capd patient and dialysis - assistant was cultured , staphylococcus aureus was isolated from the dialysis - assistant and had the same antibiotics profile as the capd dialysate culture . among the 5 ( 14% ) fungal isolates , 3 ( 8.3% )
were associated with cons ( aspergillus flavus , rhizopus spp and non - candida albicans each in combination with cons ) .
a total of 31 ( 86.1% ) episodes of peritonitis were cured . in 3 ( 8.3% )
episodes of peritonitis of polymicrobial cause , the catheters were removed and patients were switched over to hemodialysis and in 2 ( 5.5% ) episodes of peritonitis caused by mycobacterial spps , the patients died .
one patient died shortly after the start of treatment and in the other , the diagnosis was made postmortem .
pd - related peritonitis could be caused by touch contamination , catheter - related problems , bowel pathology , gynecological disease , or systemic bacteremia . despite the advances in pd system connectology , contamination at the time of the pd exchange
worldwide , gram - positive peritonitis followed by the gram - negative peritonitis are the leading causes of pd - related peritonitis .
likewise , our study also observed that the main causes of peritonitis are gram - positive ( 53% ) and gram - negative ( 28% ) microorganisms and a lesser percentage of other agents . among the gram - positive organisms ,
the staphylococcus aureus and the cons accounted for 15 ( 41.7% ) episodes of the capd peritonitis .
the staphylococcus aureus was isolated in 8 ( 22.2% ) and the cons in 7 ( 19.4% ) capd dialysates . in our study ,
one nasal carrier of staphylococcus aureus was detected in the dialysis - assistant which had the same antibiotic profiles as staphylococcus aureus isolated from the patient 's capd fluid .
the nasal carriers of staphylococcus aureus had significantly higher frequencies of exit - site infections and peritonitis than a non - carrier .
about one - fifth of the cases of peritonitis was observed to be caused by cons in this study .
also , there are studies which have reported that the majority of capd peritonitis is caused by cons
. this may primarily be due to touch contamination or due to the formation of a biofilm .
enterococci may cause between 2% and 6% of pd - related peritonitis episodes and their identification is a hallmark of a gastrointestinal origin of the infection .
overall , outcomes in enterococcus peritonitis are similar to those in cons peritonitis and are better than those of escherichia coli peritonitis . in our study , 3 ( 8.3% ) enterococcus fecalis were isolated .
listeria monocytogenes was isolated in one dialysate culture and identified by biochemical reactions and motility at 22c temperatures .
the organisms were sensitive to ampicillin , amoxi - clavulanic acid , and vancomycin and peritonitis was cured using these antibiotics .
a study has reported capd peritonitis caused by listeria monocytogenes isolated in a female patient which was sensitive to beta - lactam antibiotics .
advances in connectology have significantly reduced the overall incidence of peritonitis , particularly that caused by gram - positive organisms
. however , the incidence of gram - negative peritonitis remains at a steady level , and therefore , it has become proportionally more important .
gram - negative organisms now account for 20 - 30% of all pd - related peritonitis .
moreover , gram - negative peritonitis is often more severe and associated with worse outcomes .
gram - negative organisms were responsible for 28% of the peritonitis in this study which were equally divided between microorganisms of fecal origin and environmental origin .
gram - negative peritonitis usually occurs either because of fecal origin or transmural migration of the infecting organisms .
gram - negative peritonitis episodes attributable to transmural migration of bacteria across the bowel wall are usually associated with multiple gram - negative organisms and anaerobic organisms . in our patients ,
transmural migrations were an unlikely route of peritonitis , because none of our cultures isolated multiple gram - negative and anaerobic organisms .
we think that poor hand - washing technique and lack of access to fresh running water for hand washing may have been responsible for contamination during peritoneal dialysis exchange procedure . among the gram - negative organisms , pseudomonas aeruginosa , non - fermenter spp . , and acinetobacter spp . were the cause of peritonitis in 5 ( 13.9% ) episodes of peritonitis .
the origin may be the skin or a contaminated water bath used to heat the dialysis bag .
our study revealed that e. coli causes more peritonitis episodes as compared to the other gram - negative organisms , which is similar to the pattern observed in other parts of the world .
a study from india has reported resistance in two - third of the gram - negative organisms to the third generation cephalosporin possibily due to availability of these antimicrobials without prescriptions and misuse of antimicrobials by primary - care physicians . in our study ,
an important observation was made from the antimicrobial sensitivity profile that all the gram - negative pathogens were sensitive to quinolones , gentamicin and third - generation cephalosporins except klebsiella pneumoniae which was esbl - producer and was sensitive to imipenem . in the recent years , fungal peritonitis complicating capd is being increasingly recognized .
recent antibiotic therapy , frequent episodes of bacterial peritonitis , and immunosuppression are the major risk factors of fungal peritonitis which accounts for 1 - 15% of episodes of peritonitis in various studies .
candida albicans has historically been reported to be a more common cause than non - albicans species , but in recent reports , a shift has been observed .
now non - albicans candida may be more common and there is increasing recognition of filamentous fungi as pathogens in capd patients .
there were 2 isolates of non - candida albicans and 1 isolate each of candida albicans , rhizopus spp . and aspergillus flavus in a total of 5 fungal isolates
. the origin of fungal isolates may be from the patients skin , environment , or from the mucous membranes . in our study , mycobacterium tuberculosis ( 1 ) and mycobacterium kansasii ( 1 ) were isolated in two dialysate cultures .
chronic renal failure may lead to a defect in the cellular arm of immune response and predispose to mycobacterium tuberculosis infection .
some studies proposed that infection with mycobacterium tuberculosis is acquired by direct contamination via peritoneal dialysate , whereas other researchers believe that infection is spread from another focus of tb in the body .
a triad of abdominal pain , abdomen distension , and fever has been reported to occur in < 60% of the patients . in our patients , abdominal pain ,
distension , and cloudy fluid were the symptoms and peritonitis was not resolving in spite of the conventional broad - spectrum antimicrobial treatment .
the diagnosis of tb peritonitis requires a high index of suspicion but early diagnosis is often difficult to make .
some studies observed that despite the presence of molecular diagnostic techniques , we will depend upon conventional microbiological cultures for the identification of mycobacterial species .
however , direct microscopic smear detection of acid - fast bacilli in the ascitic fluid is insensitive , with reported sensitivity ranging from 0% to 6% and the conventional microbiological diagnostic methods are slow and may not be sensitive enough for establishing a diagnosis in a timely manner .
moreover , the validity of molecular diagnostic techniques in peritoneal dialysis patients has not been established .
treatment delay is the most significant factor contributing to high morbidity and mortality due to tb peritonitis .
therefore , it is prudent to start empirical treatment with anti - tubercular chemotherapy in capd patients with peritonitits that is refractory to broad - spectrum antibiotics while awaiting the results of the mycobacterial cultures to improve the outcome and preserve peritoneal membrane integrity .
in our capd patients , the main causes of peritonitis were gram - positive and gram - negative microorganisms and a lesser percentage of other agents .
the rate of gram - positive peritonitis was higher than that of gram - negative peritonitis .
the higher incidence of gram - positive peritonitis in our capd patients was due to their break in the sterile technique .
mycobacterial infections should be suspected in all episodes of culture - negative peritonitis especially those which do not respond to usual antimicrobial therapy .
 the objective of the study was to identify the microbiological spectrum and drug - sensitivity pattern of peritonitis in patients on continuous ambulatory peritoneal dialysis . 
 this was a prospective study done over a period of a year - and - a - half at a tertiary - care hospital in a hilly state of india . 
 the effluent dialysate bags from 36 consecutive patients with peritonitis were studied . 
 one hunderd ml dialysate fluid was processed under aseptic conditions by lysis centrifugation method . 
 microscopy and culture was done from the deposits for bacteriological , fungal , and mycobacterial isolates . 
 they were identified by colony morphology and their biochemical reactions . 
 drug susceptibility testing was done by kirby - bauer disc diffusion method . in 36 dialysates , 33 ( 91.6% ) 
 dialysates were culture - positive and in 3 ( 8.4% ) , the culture was negative . 
 a total of 36 microorganisms were isolated in 33 cultures . among the 36 microorganisms , 19 ( 52.8% ) isolates were gram - positive , 10 ( 27.8% ) were gram - negative , 5 ( 13.9% ) were fungi , and 2 ( 5.6% ) were mycobacterial isolates . 
 all gram - positive organisms were sensitive to ampicillin , amoxi - clavulanic acid , cefazolin , clindamycin , and vancomycin . 
 neither a methicillin - resistant staphylococci aureus nor a vancomycin - resistant enterococcus was isolated in gram - positive isolates . 
 gram - negative organisms were sensitive to ciprofloxacin , ceftriaxone , ceftazidime , cefepime , gentamicin , piperacillin  tazobactam and imipenem . 
 one of the gram - negative isolate was an extended spectrum beta - lactamase producer . 
 gram - positive peritonitis was more frequent than gram - negative peritonitis in our continuous ambulatory peritoneal dialysis patients . 
 mycobacterial causes were responsible for peritonitis in patients with culture - negative peritonitis which was not responding to the conventional antimicrobial therapy . 
Introduction
Materials and Methods
Results
Discussion
Conclusion