A study on the prevalence of asymptomatic bacteriuria and their antibiogram pattern among pregnant women in a tertiary care hospital.
ASB occurs in 2-10% of pregnancy, a similar prevalence as seen in non-pregnant women.!5) However, pregnancy enhances the progression of asymptomatic to symptomatic bacteriuria, which could lead to symptomatic cystitis [30%] and pyelonephritis (up to 40 percent) in pregnant women. The smooth muscle relaxation and subsequent ureteral dilatation that accompany pregnancy are thought to facilitate the ascent of bacteria from the bladder to the kidney.
Successful treatment reduces the rate of subsequent UTI by 80-90 percent. Studies have also reported consistently a decrease in acute pyelonephritis later in pregnancy from 20-40% to 2-4%  of women who have been identified with asymptomatic bacteriuria in early pregnancy and treated. Pyelonephritis could lead to maternal and fetal complications like Low birth weight, preterm labour, pre-eclamptic toxaemia and anemia of pregnancy. [7,5]
In view of close association of ASB with adverse maternal and fetal complications, plus the ability to avoid the significant consequences with effective treatment, the screening of pregnant women for bacteriuria have been recommended by various studies.
Prevalence rates show high degree of variations between studies depending on the ethnic and socioeconomic mix.  Data on the current distribution and antimicrobial drug susceptibility patterns among urinary bacterial isolates from pregnant women in India is limited. In view of this fact and very few studies have been reported from India, as ASB screening is not carried out routinely probably due to cost implication, this study was undertaken to determine the prevalence of ASB and their antimicrobial susceptibility pattern among pregnant women attending our tertiary care hospital serving the suburban areas of Chennai.
MATERIALS AND METHODS: Study area: This study was carried out in our tertiary level referral and teaching hospital, which is serving the suburban population of Chennai. In this cross sectional study, clean catch midstream urine samples [MSU] from 281 pregnant women who attended routine antenatal check- up without symptoms of urinary tract infections during March 2012 to March 2013 were included. This was an analysis of data generated from the records of urine samples received in the laboratory during study period.
Samples received in a leak proof sterile container were processed within one hour. All samples were inoculated onto blood agar, nutrient agar and Mac conkey agar plates using a calibrated loop [0.001ml] and were incubated overnight at 370C and examined next day. Colony counts yielding bacterial growth of 105cfu/ml were considered significant as per recommendations. All isolates were identified by standard laboratory techniques. 
Antibiotic susceptibility was done by Kirby Bauer disk diffusion method as per CLSI guidelines. Drugs that were tested include Ampicillin, Amoxicillin, Ciprofloxacin, Norfloxacin, Nitrofurantoin, Ceftriaxone, Gentamicin, Cotrimoxazole and Augmentin. Two antibiotics tested only against gram-positive isolates were Oxacillin and Vancomycin. 
Data Management and Analysis: Data were entered into a database designed using MS Excel spreadsheet and analyzed using SPSS statistical software package [version 20]. Proportions for categorical variables were compared using chi-square test. P value less than 0.05 was considered statistically significant.
Table 1: Prevalence of ASB among pregnant women TOTAL NO OF NO OF SAMPLES % OF ASB SAMPLES SCREENED POSITIVE BY CULTURE PREVALENCE 281 39 13.87
A total of 281 MSU samples received during March 2012 and March 2013 were included in this study. Of these, 235 [83.62%] were sterile, 39 [13.87%] showed significant and 7 [2.49%] showed insignificant growth. None of the samples have yielded more than one isolate.
Majority of ASB positive subjects were in the age group of 25-29 yrs [38.46%]. Statistical analysis of ASB with respect to age group did not reveal any significance. About 30.76% were in the age group of 20-24 yrs, 28.2% in 30-34 yrs and 2.56% were more than 35 yrs of age.
Based on the trimester, 132, 65 and 84 subjects were in 1, 2 and 3 trimester of pregnancy. Of this, 28[21.2%], 5[7.69%] and 6[7.12%] of ASB positive subjects were in first, second and third trimester. This study showed high prevalence of ASB in pregnant women of first trimester.
According to gravid status, 96 pertained to primi, 140 to second and 45 to multigravida. occurrence of ASB was observed more among multigravid women [41.02%].
E.coli was the most common organism isolated with the total of 26[66.66%] followed by Methicillin sensitive staphylococcus aureus 6 [15.38%], klebsiella pneumoniae 5[12.82%] and CONS 2[5.13%].
High percentage of resistance has been observed for the antibiotics Gentamicin [74.35] and cotrimoxazole [74.35]. The percentage of isolates resistant to ampicillin was also found to be as much as 69.23percent The susceptibility pattern of the isolates showed that most of them were highly sensitive to Augmentin [5.12%], Amikacin [5.12%], Ceftriaxone [10.25] and Nitrofurontoin [20.51]. 100% 0f all gram positive organisms were sensitive to oxacillin and vancomycin tested.
DISCUSSION: In our study, the prevalence rate of ASB among pregnant women screened was found to be 13.87%. This was in accordance with the findings reported by T. Jeyaselan et al  and Balamurgan et al  in a south Indian population and comparable to the prevalence quoted from Tanzania and Sudan (14%).  Other Indian studies have reported 10% from Tumkur,  8.4% in Vishakpatnam,  9 and 11% from Raichur and Kolkata, [14,15] this is slightly lesser than our findings.
However, there are not many studies in the prevalence of ASB in India. The prevalence rates detected from our study is lesser than the rates quoted in other studies from Lucknow(17%)  and Hyderabad (16%). 
These variations in rate can be explained by the fact that differences in the environment, social habits of the community and educational standard of the population. Another reason could be as a result of improper genital hygiene practices as pregnant women find it difficult to clean their anus properly. [3,5]
In our study, age group 25-29 years had the highest infection rates (38.46%), followed by 20-24 years (30.76%), 30-34 yrs [28.2%] and those who were more than 35 years (7.69%). The aforementioned age group (26-30 years) was also observed in the previous studies to have the highest incidence. A possible explanation would be due to decreased glycogen deposition and reduced lactobacilli related to aging, bacterial adherence and invasion is enhanced. However, statistical analysis of ASB prevalence with respect to age group did not reveal any significance, this agrees with earlier studies.
Similar study conducted by Marahatta et al  showed high prevalence among pregnant women in first trimester which seems similar to our study. A statistically significant association was observed for the ASB occurrence and first trimester. This may be related to anatomical and physiological changes related to month of pregnancy.
There was a statistically significant difference in the prevalence of ASB with respect to gravid status [P <0.0001]. Our study observed high prevalence in multigravida. This could be explained by the fact that multigravid female might have had many children before the present pregnancy and it has been reported that multiparity is a risk factor for acquiring ASB in pregnancy. [3,18]
The most common uropathogen isolated in our study was E.coli (66.66%), which is similar to other reports. (Table 7)
Another important observation of this study was the increasing trend in the prevalence of S. aureus infection (15.28%). Very few studies have reported such a high rate. This dramatic increase in prevalence rate can be attributed to the emergence and global spread of staphylococcus aureus. Hence, recognizing this change in the spectrum of uropathogens remains important to guide changes in empirical antimicrobial therapy. The other organisms isolated were Klebsiella pneumoniae and CONS. They are less common causes of UTI.
Antimicrobial resistance patterns change over time and found to differ in different geographical locations, 74.34% of total isolates showed resistance to Cotrimoxazole. Our findings are in accordance with various Indian studies. [11,20]
The broad-spectrum activity of fluoroquinolones has made them as one of the best therapeutic options for UTI. Although many studies have reported high sensitivity to this group of drugs,  our findings are slightly different. A resistance rate of ciprofloxacin was 38.46% against 15.38% of isolates resistant to Norfloxacin.
This might be due to indiscriminate use of ciprofloxacin as they have been prescribed empirically in the last few years. Low sensitivity to Ampicillin has been observed which seems similar to the finding reported by Imade et al could have been contributed by an increase in Ampicillin prescribing practices in recent years [20,21] High resistance observed for cotrimoxazole, ciprofloxacin and ampicillin.
In this study, the most useful antibiotics as predicted by their sensitivity rates were amoxicillin [96%], nitrofurantoin [79%], norfloxacin [84%], ceftriaxone [89%] and augmentin [94%]. Sensitivity to Amoxicillin was encouraging and it can be safely prescribed during pregnancy as first line antibiotic.
CONCLUSIONS: Significant bacteriuria was observed in asymptomatic pregnant women in our study population and bacterial spectrum and their resistance pattern was observed. So this study emphasizes the need for screening of pregnant women for ASB and periodic monitoring of uropathogens for antibiogram pattern as this data not only reduces the prevalence but also helps in rationalizing the antibiotic usage to restrict further emergence of resistance. Our study revealed that amoxicillin is the most effective drug that can be recommended for ASB during pregnancy.
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(1.) Madhu Udawat
(2.) Nithyalakshmi J.
(3.) Sumathi G.
(4.) Swapna Mallure
PARTICULARS OF CONTRIBUTORS:
(1.) Associate Professor, Department of Obstetrics and Gynaecology, SMMCRI.
(2.) Associate Professor, Department of Microbiology, SMMCRI.
(3.) Professor and HOD, Department of Microbiology, SMMCRI.
(4.) Assistant Professor, Department of Microbiology, SMMCRI.
NAME ADDRESS EMAIL ID OF THE CORRESPONDING AUTHOR:
Dr. Nithyalakshmi J, 5/7, Sethammal Colony, Varalakshmi Apartment, Alwarpet, Ch-18.
Date of Submission: 30/06/2014.
Date of Peer Review: 01/07/2014.
Date of Acceptance: 07/07/2014.
Date of Publishing: 14/07/2014.
Table 2: Prevalence of ASB among pregnant women with respect to age group AGE NO. OF CASES NO. OF CASES POSITIVE % OF CASES GROUP SCREENED BY CULTURE[n=39] POSITIVE FOR ASB 20-24 73 12 30.76 25-29 98 15 38.46 30-34 105 11 28.20 >35 5 1 2.56 Table 3: Prevalence of ASB according to trimester Trimester No. of cases No. of cases % of case screened positive for ASB positive of ASB 1st 132 28 21.2 2nd 65 5 7.69 3rd 84 6 7.14 Table 4: Prevalence of ASB according to Gravida Gravida No. of cases No. of cases % of case screened positive for ASB positive of ASB 1[primi] 96 10 25.64 2 140 13 33.33 >2[multi] 45 16 41.02 Table 5: Distribution of uropathogens isolated from ASB among pregnant women Organism No. of Isolates % of Isolated [n=39] Isolates E.coli 26 66.66 Klebsiella 5 12.82 Staph. aureus 6 15.38 CONS 2 5.13 Table 6: Resistance rates of uropathogens isolated Sl. ANTIMICROBIAL RESISTANCE NO. AGENT TESTED %[n] 1 Ampicillin 69.23 2 Amoxillin 23.07 3 Augmentin 5.12 4 Ciprofloxacin 38.46 5 Nitrofurontoin 20.51 6 Norfloxacin 15.38 7 Amikacin 5.12 8 Gentamicin 74.35 9 Vancomycin 0 10 Cotrimoxazole 74.35 11 Ceftriaxone 10.25 12 Oxacillin 0 Table 7: Isolated organisms across various studies Present Kerure SB Alemu Organism study % et al., % et al., %    E. coli 66.6 77.7 47.5 Klebsiella 12.82 6.66 10 Proteus Nil Nil Nil Pseudomonas Nil Nil Nil Citrobacter Nil 2.22 10 S. aureus 15.38 11.11 22.5 CONS 5.13 Nil 5 Jeyaseelan Danizen Jeyalakshmi Organism et al., % et al., % et al., %    E. coli 69 57.6 57.4 Klebsiella Nil 30.6 19.21 Proteus Nil Nil 4.25 Pseudomonas Nil 12.6 4.25 Citrobacter 14 Nil Nil S. aureus Nil 4.8 10 CONS 15 Nil Nil
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|Title Annotation:||ORIGINAL ARTICLE|
|Author:||Udawat, Madhu; Nithyalakshmi, J.; Sumathi, G.; Mallure, Swapna|
|Publication:||Journal of Evolution of Medical and Dental Sciences|
|Article Type:||Clinical report|
|Date:||Jul 14, 2014|
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